90 



LOG SCALING FOR BOARD MEASURE 



logging and milling ends of the business, as if they were under separate 

 management. Woods scaling also checks the accuracy of timber esti- 

 mates, whenever the timber from given areas is scaled separately in 

 logging. 



When the purjjose is to determine the basis for paying saw crews, logs are 

 scaled in the woods before skidding. When standing timber is sold on the basis 

 of the log scale, the scaling is done at the skidways or landings before removal 

 from the tract or vicinity. The mixing of logs cut from two or more tracts must 

 be avoided by any necessary measure such as sawyers' marks, or scahng in the 

 woods. Where no question of sale is involved, the logs are scaled wherever it is 

 most convenient. Logs are usually re-scaled on the log deck. Where logs are 

 rafted and sold, they usually are scaled in the water. 



81. The Cylinder as the Standard of Scaling. A log rule does not 

 give an exact scale of lumber which will be or can be sawed from logs 



(§ 46). The log rule is an arbitrary 

 standard fixing the quantity of 1-inch 

 lumber said to be contained in logs of given 

 diameters and lengths. When the top or 

 small end of the log inside the bark deter- 

 mines the diameter, as it does for all board- 

 foot log rules in common use, these rules do 

 not include any boards or pieces sawed 

 from the taper or swell of the log. The 

 scaler must therefore pay no attention to 

 that portion of the contents of the log 

 which lies outside of this cylinder, no 

 matter whether this portion be sound or 

 defective. On the butt end of a log, the 

 contents to be scaled lies within a smaller 

 circle representing the area of the top end 

 of the log, or the cross-section of the 

 cylinder whose diameter is this top end. 

 This cylinder must coincide in position 

 with the axis of the log, so that the center 

 of the cross-section or area to be scaled 

 coincides with the center of the butt or 

 larger end of the log. Common errors in scaling are the shifting of the 

 scaled cylinder towards one side to avoid defects, and the offsetting of 

 defects within the cylinder against sound short lumber which may be 

 scaled from the taper. 



82. Deductions from Sound Scale versus Over-run. Log rules 

 give the scale of this cylinder in sound lumber and do not allow for 

 defects. The standard scaling practice is to make deductions from 



Fig. 11. — Projection of area 

 of top end of log on butt 

 section, showing portion of 

 butt to be scaled. The 

 circle A represents the area 

 to be scaled. The presence 

 of defect in area C does not 

 justify the shifting of this 

 circle to position B but de- 

 ductions for defect must be 

 made from A. D is the 

 geometric center of the log 

 and of the scaled area A . 



